Providing frost protection for fruit and nut trees; is a common but necessary occurrence, usually in early spring. Freezing of buds, flowers, or fruit can be detrimental to the crop, but fortunately, there are several ways to help protect against frost damage.
Generally, all frost/cold protection methods consist of one or more of the following principles according to the Washington State University Irrigated Agricultural Research and Extension Center:
(1) good site selection for adequate air drainage;
(2) mixing of air (for example, wind machines or helicopters);
(3) direction convention heating of the air (heaters or under-tree sprinklers);
(4) radiant heating directly to the plant (for example, heaters or under-tree sprinklers);
(5) release of the latent heat of fusion (for example, freezing water directly on the plant via over-tree sprinklers);
(6) release of the latent heat of condensation (for example, humidification, fogs or sprinklers);
(7) radiative heat loss interception (for example, fog or cover);
(8) utilization or soil heat storage (for example, bare soils);
(9) thermal insulation (for example, covering foams or greenhouses);
(10) bloom delay (for example, over-tree sprinklers and/or tree wraps and paint);
(11) planting cold hearty and/or late blooming varieties; and
(12) genetic development of cold resistant plants.
Insofar as sprinklers are a common link to many of the above described modes of protection, it is critical to prevent ice formation on the sprinkler itself which would otherwise render the sprinkler useless as a frost protection device. All sprinklers inevitably freeze up at some point in varying weather conditions and are unable to function properly. Accordingly, the present invention relates to a removable clip that is attachable to a variety of rotating type sprinklers that will enable the sprinkler to function in severe weather conditions. When the clip in accordance with this invention is installed on the sprinkler body, a small burst of water is deflected off the clip and onto the top of the rotating stream distributor plate as well as onto other adjacent parts of the sprinkler body. The deflected water helps warm the rotating plate and the sprinkler body and keeps water flowing across these parts, thereby discouraging ice build up. The clip is constructed so that it can be easily attached and removed, but it will be appreciated that the clip could also be made integral with the sprinkler body itself, or with the sprinkler rotating distributor plate.
In an exemplary embodiment of the invention, a clip is described for use with a rotating sprinkler manufactured by the assignee, Nelson Irrigation Corporation, and known as the R-10 "mini" rotator. The sprinkler includes a sprinkler body mounting a nozzle for emitting a single vertical stream upwardly into a contoured groove within a rotatable distributor plate which is supported by the sprinkler body directly above and in axial alignment with the nozzle axis. The stream emitted from the nozzle causes the rotator plate to rotate about its own axis (the speed of rotation is controlled by a viscous brake also mounted within the sprinkler body) and the groove in the rotator plate is configured to redirect the stream substantially horizontally radially outwardly from the sprinkler body. The controlled rate of rotation of the rotator plate results in a substantially single stream rotating relatively slowly about the axis of the rotator plate. The frost clip in accordance with this invention is mounted to a sprinkler body arm which is otherwise directly in the path of the rotating stream. The sprinkler body arm is typically tapered to a point to split the stream without creating a "blind spot" but, in this instance, the frost clip deflects a portion of the stream back onto the rotor plate and adjacent the sprinkler body portions.
In the exemplary embodiment, the clip includes a relatively flexible horizontal portion adapted to clip onto the vertical portion of one of the sprinkler body arms, and also includes a vertical portion having an integral groove which faces radially towards the axis of rotation of the rotator. As the rotator plate rotates, the single stream will impinge upon the frost clip groove and direct the water back on top of the rotor plate and adjacent sprinkler body portions.
Thus, in accordance with the broader aspects of the invention, there is provided in a rotary sprinkler having a nozzle for emitting a primary stream along a center axis of the nozzle and a rotary distributor plate spaced from the nozzle for redirecting the stream to achieve a desired sprinkling pattern, the improvement comprising means for intermittently deflecting at least a portion of the stream redirected by the distributor plate back onto the distributor plate.
It will be apparent that the frost clip in accordance with this invention helps keep ice from building up on the plate, allowing it to run at lower temperatures than are possible without the clip. Moreover, the back splash feature has only a minimal effect on the distribution pattern of the sprinkler. Other objects and advantages will become apparent from the detailed description which follows.